Press bed drive



April 21, 1942. s. A.-HUFFMAN I PRESSY BED DRIVE Filed Aug. 26, 1939 4Sheet-Sheet 2 INVENTOR I jamuelAf/ufif'man April 21,1942. A UFFMAN2,280,091

PRESS BED DRIV-E Filed Aug. 26, 1939 v 4 Sheets-Sheet 3 INYENTOR April21, 1942. s. A. HUFFMAN 2,280,091

PRESSBED DRI-VE Filed 1m 26, 19319 f 4 Sheets-Sheet 4 58/72049/4.Huffman MIM Patented Apr. 21, 1942 UNITED STATE PR E SS BED DRIVE SamuelA. Huflman, Ayalon, Pa., assignor to Miller Printing Machinery 00.,Pittsburgh, Pa., a corporation of Pennsylvania Application Au ust 26,1939, Serial No. 292,105 g 8 Claims.

, This invention relates to mechanism for reap rocating thejbed of aflat bedand cylinder press.

The demand for higher efficiency in press" operation has led to thedesign ofv presses running at higher and higher speeds, despite certainfactors entering into press operation which tend definitely to limit themaximum permissible operating speed. It is the general object of thisinvention to extend the limit on press speed a novel construction. andarrangement of parts whereby higher operating speeds may be safelyattained than with the constructions known heretofore.

The weight of the reciprocating bed is probably 7 the principal limitaton upon press speed, because of necessityfor accelerating the bed fromrest to maximum speed and then decelerating it to rest twice during eachcomplete operating cycle. For this reason, attempts havebeen made toreduce the weight of the bed. Here again, however, a limit is imposed bythe necessity that the bed be rigid enough to avoid any materialdeflection under the pressure exerted, thereon by thecylinder. ,Ribbedbeds have been resorted to for rigidity butthe permissible depth of theribs is limited by the clearances necessary between the bed and thereversing gears as previously installed. The location of the reversinggears previously employed,-furthermore, as well asthe character of thereversing hanger carried bythe reducing the deflection of the bedbetween tracks .by reducing the span between the two inner tracks of afourtrack press, for example.

Other novel features and advantages of ,the invention will be more fullypointed out hereinafter in the course of the followingdetaileddescription and explanation in which reference is made to, theaccompanying drawings illustrating 'a present preferred embodiment. Inthe draw ings:

'Fig. 1 is a plan view of a presshaving'thein i vention incorporatedtherein, showing the parts in position for effecting a return stroke ofthe f stantially along the bed, have. been such that the inner bedtracks are achieved. In a preferred form of the invene tion, I provide areversing hanger disposed substantially centrally of the bed cooperatingwith reversing cranks which. successively engage the hanger near theends of the press. I also dispose the gear drive for the reversingcranks andpress cylinder on one side of the press. This constructionprovides a greater depth of free space across the machine below thecylinder than is present in previous press constructions. Forthisreason,

the overall height of the press may be less than was formerly required.The novel construction of thefhanger and reversing cranks, furthermore,v

as well as the location of the reversing gears at one side of the frame,permits the several tracks on which the bed is supported forreciprocation to be spaced substantially uniformly, thereby bed,partsbeing omittedforclearness; a

Fig. 2 is a sectional view taken'substantially along-the plane of lineIL-I Iof Fig. 1, showing the bed at a point inits printing stroke; 7Fig. 3 is a' sectional view taken along the plane of line III--III ofFig. 1, showing the parts positioned for a return stroke of the bed;

Fig. 4 is a partial sectional view taken sub;- plane of line IV-IV ofFig. 3; and r o Fig. 5 is a View partly in elevation and partly insection along the plane of line V-V of Fig. 4. 7 Referring now in detailto the drawings, a press of the flat bed and cylinder type includes sideframes I 0 and II connected at their ends by end castings l2 and I3. Thepress cylinder 14 has trunnions journaled in bearings l5 mounted inupward extensions. Hi from the side frames l0 and H. The bed IT issupported reciprocably below the cylinder on tracks [8 carried on across beam 19. Roller bearings 20 are disposed be tween the tracks l8and the bed and thelatter is held on-the tracks by gibs 2|. Bearers 22on the cylinder cooperate with bearers 23 on the bed as the latterpasses beneath the cylinder on a first in one direction of rotation uponreciproca- ;;tion of the bed in one direction and then in the oppositedirection of rotation upon reciprocation of. the bed in the oppositedirection. The bed I! is provided with the usual ink plate 26.

The construction describedso far is conventional and for that reason itis unnecessary to go sprocket 29 is secured to a main drive shaft 36which is journaled in bearings 3| in the webs of the two tracks I8nearest the side frame H. A fly-wheel 36a is mounted on the shaft 36. Apinion 32 on the shaft 36 meshes with a bed reversing gear 33 secured toa shaft 34. shaft 34 is journaled in bearings 35 and 36 formed in theside frame II and the adjacent inner track l8. A bed reversing crank 31is secured to the shaft 34 adjacent its inner end and is provided with aroller 38 journaled on a crank pin 39. i a

The roller 38 is adapted to engage a hanger 46 depending from the bedI1, in a manner to be described further hereinafter. The hangercomprises a ribbed casting having plane bearing surfaces 4| and 42disposed at angles to the horizontal.

The'pinion 32 also meshes with an intermediate gear43 secured on a shaft44. Theshaft 44 is journaled in bearings disposed in the side frame IIand the webs of one of the tracks 16, in the same manner as the bearings35 and 36. The shaft 44 has secured to it a gear 43a which meshes with agear 45 secured to one of the trunnions of the cylinder 14. The gear 43also meshes with a reversing gear 46 secured to a shaft 41. 'The shaft41 is journaled in bearings 48 and 49 similar to the bearings 35 and 36for the shaft 34. The shaft 41 also has a crank 56 at the inner endthereof provided with a crank pin 5| having a roller 52 for engagementwith the bearing surface 42 of the hanger 46.

A gear 53 has a grooved collar 54 integral therewith (see Fig. 4) and issplined on a sleeve 55 secured to the shaft 44. The gear 53 meshes witha rack 56 secured to the bed 11 for driving the bed during the constantspeed portion of its printing stroke. The gear 53 is shiftedaxiallyalong the sleeve 55 by means to be described shortly while the bed isbeing decelerated and reversed after a printing stroke. 1

The gear 53 also meshes with a gear 51 se- 7 cured to a shaft 58. Theshaft 58 is journaled in bearings 59 in the webs of the two tracksnearest the side frame H and is slidable axially therein by the samemeans which shifts the I gear53. A gear 66 on the shaft 58 has a groovedcollar 6| integral therewith and is adapted to mesh with a rack 62 onthe bed l1 to effect the reverse stroke of the latter. 7

A pinion 63 on the shaft 44 meshes with a cam gear 64 secured to a shaft65. The shaft 65 is journaled in bearings 66 similar to the bearings 59of the shaft 58. A gear 61 on the shaft 65 has a barrel cam 68 formedintegral therewith having a groove 69 therein. A shifter a A shifteryoke 14 pivoted on the beaml6 at 15 has tongues 16 entering the groovein the collar 54 formed on the gear 53. The shifter yokes 16 and 14 areconnected by a link 11 pivoted thereto. Rotation of the cam 68 thuscauses simultaneous axial shifting of the gears 53, 51 and 66.

The gear 61 meshes with a gear 18 for operating a cam shaft (not shown)or other means for periodically actuating auxiliary control devices suchas the valves between the suction feet of the feeder and a vacuum pump(not shown).

The cam gear 64 has a groove 19 formed in one side thereof. A crank 86is rotatable on a stub shaft Bl secured in the web of the track l8nearest the side frame II, and has a roller 82 in the groove 19. A gearsegment 83 secured to the crank 86 meshes with a pinion 84 secured to ashaft 85. The shaft 85 extends between the side frames I6 and II, beingjournaled in bearings 86 therein, the webs of the tracks [8 being boredto admit the shaft. The shape of the groove 19 is such that rotation ofthe gear 64 causes oscillation of the crank 86 and the segment 63. Thisoscillation is transmitted to the pinion 84 and shaft 85. The latter haseccentrics 81 which, by means of push rods 68, actuate the bearings l5supporting the trunnions of the cylinderv l4. These bearings are mountedin eccentrics so that partial rotation of the latter raises or lowersthe bearings.

In explaining the operation of the press bed drive described above itwill be assumed that the bed 11 is at the left end of its stroke asindicated in Fig. 2 in chain lines. The reversing gear 33 being drivenclockwise by the motor 21, the roller 38 exerts downward pressure on thebearing surface 4| of the hanger, thereby accelerating the bed for aprinting stroke (i. e., toward the right in Fig. 2). After half arevolution of the gear 33 the roller 38 departs from the bearing surface42 of the hanger and at that instant the rack 56 engages gear 53. Thedesign of the cam 66 and the setting thereof on the shaft 65 is suchthat the gear 53 is in vertical alinement with the rack 56 at this-instant. Thus, after being accelerated to maximum speed by the crank 31,the bed moves through the constant speed portion of its travel. Duringthe actual printing portion of the stroke, the cylinder is drivenfrictionally by its contact with the bearers 23, the teeth of thecylinder gear 45 being appropriately relieved for this purpose.

At the instant when the trailing end of the bed passes the verticalcentral plane through the cylinder l4, the roller 52 is in the positionshown in solid lines in Fig. 2, and is thereupon engaged by the bearingsurface 42 of the hanger 46. Continued counterclockwise rotation of thecrank 56 through 90 to the position shown in chain lines causes the bedto be decelerated. It is then reversed as the crank passes'beyond thechain line position.

While the bed is being decelerated and reversed by the crank 56, thebarrel cam shifts the yokes 16 and 14 to the position shown in Fig. 4,sothat the gear 66 is ready to engage the rack 62 to move the bedthrough the constant speed portion of its travel on the reverse stroke.This engagement occurs when the crank 56 has rotated to a posi- 3 0112180 from that in which it is solid lines in The cam groove in the gear19 causes oscillation ofthe crank 86 and the segment 83 at the propertime tocausethe bearings", l tobe raised so that the cylinder; lkclearsthe formon the bed when the latter makes its reversestroke.

When thebed hasreached the pointin itslireverse stroke at which the rack62 passes beyond the gear 60, the roller38 of the crank 31 is in theposition shown in solid lines in Fig. 2 and engages the bearing surface4| "of the hanger to decelerate the bed on continuedclockwiserotationofthe reversing gear 33. A full cycle of operations is thus completed andcontinuedoperation of the drive involves merely a repetition ofheretofore. This means that the overall height of the machine maybereduced. I The drive gears, being located "outside the press frame, maybe enclosed' in an oil filled housing; A further advantage of greatimportance is the fact thatthere are only two gear meshes between themain drive shaft andthecylinder or the thecycle described. It will beunderstood that the oscillation of theshaft 85 is such as to restore thebearings of the cylinder to the position in which the cylinder hasfirmengagement with the form on the'bed, before the latter reaches thecylinder on the printing strokel It will also be understood that themovement of the bed is positively controlled throughout its stroke inboth directions; so that the racks 56 and62 mesh properly with thegears53 and 60. during the constant speed portion, of the printing andreversingstrokes. It will be apparent that the inventionis characterizedby numerous advantages over present bed drives as known heretofore; Theuse of ahangerhaving both its bearing surfaces in alinement and thedisposition of the reversing" gears beyond one side of the press makesit possible to place the inner tracks 18. closer together,

thereby equalizing the, distance between them with the distance betweenthem and the outermost tracks. This shortens the span of .thebed betweenthe inner tracks and limits the deflec tion of the bed during printing.By way of comparison, the inventionpermits the distance betweenthe outerandinner tracks tobe as much as 90% of the distance betweenthe innertracks as comparedto about 50% forthe previous constructions. Themaximum and minimum track spacings for a typical example of my inventionare 18 andl'l compared to 25 and 13 for the former construction.

By locating the reversing gears beyond the side frame instead of betweenthe inner track webs, it is possible to use gears of larger diameter,thus reducing-the tooth pressure and permittingthe use of less expensivematerial such as cast iron,

instead of the more expensive heat treated alloy steels. The reversinggears are subject to the tremendous forces involved in rapidacceleration and deceleration of the bed and their strength is adefinite limit upon the operating speed of the press. By virtue of thelocation of the reversing gears beyond the side frame, the tooth widththereof may be increased, further to reduce the unit pressure, withoutrequiring greater spacing between the inner track webs as would be thecase if the reversing gears were located therebetween.

The main driving gears, furthermore, may be of the single or doublehelical type which are particularly advantageous at higher speedsbecause of greater strength, quiet operation and freedom of vibration.It is not possible to employ this type of gears in press drives as previously constructed.

The closer spacing of the tracks makes it possible to reduce the.overall'depth'of the bedfor a given permissible maximum deflection.This reduces the weight of the bed and raises the maximum safeoperating'speed. I

The flywheel shaft is near the centerofthe press, thereby reducing thegear shock transbeds This compares with four ormore meshes in previousdrives. The lost motion representing cumulativetooth clearances is thusgreatly reduced- This minimizes the so-called bumping of the registersegment usually mounted on the cylinder and register rack on the bedtoinsure perfect registrationon beginning of the printing operation. Thereduction in the'number of gear meshes also makes the pressexceptionally smooth running, which characteristic is reflected in alonger useful lifeiof the press.

' It will be noted that the rack 56 through which the bed is driven on aprinting stroke is located generally centrally of the bed, whereastherack 62 through which the bed isdriven on a reverse stroke is locatedadjacent the edge of the bed which carries the inker driving rack 23a.This arrangement has been found particularly ad:- v'antageous in that itreduces any tendency which the bed might otherwise have to skew upon thereverse stroke. The relatively heavy load imposed upon movement of thebed in a printing stroke is takenby the generally centrally disposedrack 56. On the reversestroke of the bed the principal load is imposedbythe inker, as there is very little resistance to the reverse movement ofthe bed itself. By positioning the rack 62 adjacent the edge of the bedwhich carries the rack 23a the force which is consumed mainly in drivingthe inker on the reverse stroke is applied adjacent the edge of the bedat which such force is transmitted to the inker, thus reducing to aminimum the lateral distance between the points of application of forceand hence reducing the tendency of the bed to skew I upon the reversestroke.

Although I have illustrated and described but a preferred embodiment ofthe invention, it will be understood that changes in the constructionand arrangement disclosed may be made without departing from the spiritof the invention 0 the scope of the appended claims,

I claim: 1. In a press, a frame, a bed reciprocable alon tracks on saidframe, reversing shafts journaled in said frame adjacent the endsthereof, a hanger.

depending from said bed having inclined plane bearing surfaces extendinglaterally therefrom,

and the other of said gears, and a cylinder journaled in .said frame forcooperation with said bed, said cylinder being driven directly from saidintermediate shaft.

2. In a press, a frame, a bed reciprocable along tracks on said frame,reversing shafts journaled in said frame adjacent the ends thereof, ahanger depending from said bed having inclined plane bearing surfacesextending laterally therefrom, cranks on said shafts having rollersadapted to engage said surfaces respectively when the bed nears the endsof its stroke, said surfaces and rollers lying in the same planelongitudinally of the press, gears on said shafts, a main drive shaftderiving its power from outside the press having a pinion thereonmeshing with one of said gears,

an intermediate shaft having a gear thereon meshing with said pinion andthe other of said gears, and a cylinder journaled in said frame forcooperation with said bed, said cylinder being driven directly from saidintermediate shaft.

3. In a-press, a frame, four parallel tracks on said frame extendinglongitudinally thereof and spaced across the Width of the frame, a bedreciprocable along said tracks, the minimum center-to-center distancebetween adjacent tracks being at least 75% of the maximumcenter-tocenter distance between adjacent tracks, reversing' shaftsjournaled in said frame adjacent the ends thereof, a hanger dependingfrom said bed having inclined plane bearing surfaces extending laterallytherefrom, cranks on said shafts having rollers adapted to engage saidsurfaces respectively when the bed nears the ends of its stroke, gearson said shafts, a main drive shaft deriving its power from outside thepress having a pinion thereon meshing with one of said gears, anintermediate shaft having a gear thereon meshing with said pinion andthe other of said gears, and a cylinder journaled in said frame forcooperation with said bed, said cylinder being driven directly from saidintermediate shaft.

4. In a press, a frame, a bed reciprocable along tracks on said frame,reversing shafts journaled in said frame adjacent the ends thereof, ahanger depending from said bed having inclined plane bearing surfacesextending laterally therefrom, cranks on said shafts having rollersadapted to engage said surfaces respectively when the bed nears the endsof its stroke, gears on said shafts, a main drive shaft deriving itspower from outside the press having a pinion thereon meshing with one ofsaid gears, an intermediate shaft having a gear-thereon meshing withsaid pinion and the other of said gears, and a cylinder journaled insaid frame for cooperation with said bed, said cylinder being drivendirectly from said intermediate shaft, all said gears being locatedoutside of said frame.

5. In a press, a bed, an inker, means disposed in the vicinity of thelongitudinal center line of the bed for driving the bed upon a printingstroke, means carried by the bed at an edge thereof for driving theinker and means disposed adjacent said inker driving means for drivingthe bed upon a reverse stroke.

6. In a press, a bed, an inker, means for driving the bed upon aprinting stroke, means carried by the bed for driving the inker andmeans for driving the bed upon a reverse stroke, the means for drivingthe bed upon a reverse stroke being disposed adjacent the inker drivingmeans and nearer such means than the means for driving the bed upon aprinting stroke.

'7. In a press, a bed, an inker, a rack connected with the bed throughwhich the bed is driven upon a printing stroke, a rack connected withthe bed through which the bed is driven upon a reverse stroke and meanscarried by the bed for driving the inker, the second mentioned rackbeing disposed adjacent the inker driving means and nearer such meansthan the first mentioned rack.

8. In a press, a bed, an inker, a rack carried by the bed and disposedin the vicinity of the longitudinal center line of the bed through whichthe bed is driven upon a printing stroke, a second rack carried by thebed at an edge thereof for driving the inker and a third rack carried bythe bed and disposed adjacent said edge of the.

bed through which the bed is driven upon a reverse stroke.

SAMUEL A. HUFFMAN.

